CVE-2021-0266Network attack vector

Unauthenticated device takeover via hard-coded cryptographic keys

Published Apr 22, 2021 · Updated Sep 17, 2024

Hard-coded keys in affected Juniper Networks Junos OS cSRX releases allow remote attackers to take control through management services. Juniper states that cSRX software contains multiple embedded cryptographic keys, but it does not identify the key material, code locus, or management protocol that accepts them. Network access to an exposed device-management service is sufficient, with no authentication or user interaction required; successful use grants control of the cSRX instance.

CVSS severity8.1
High
EPSS probability0.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded keys in affected Juniper Networks Junos OS cSRX releases allow remote attackers to take control through management services. Juniper states that cSRX software contains multiple embedded cryptographic keys, but it does not identify the key material, code locus, or management protocol that accepts them. Network access to an exposed device-management service is sufficient, with no authentication or user interaction required; successful use grants control of the cSRX instance.

The record

CVE
CVE-2021-0266
Published
Apr 22, 2021
Updated
Sep 17, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-798, CWE-321, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20.3 <20.3R2
  2. Affected versionversion=20.4 <20.4R2
  3. Affected versionversion=unspecified <20.2R3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=20.3 <20.3R2; version=20.4 <20.4R2; version=unspecified <20.2R3

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1Juniper Networks, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
CWE-321Use of Hard-coded Cryptographic Key
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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